Thermal and/or thermal-acoustical shields, to which the presently described embodiments are an improvement, have long been known in the art. Such shields are used in a wide variety of applications, among which are shielding in space crafts, automobiles, home appliances, electronic components, industrial engines, boiler plants and the like, and are commonly referred to as heat shields, acoustical panels, thermal barriers, vibrational barriers, acoustical barriers, insulating shields, and the like. As used herein, such terms are considered interchangeable. Some of such shields have proportionally smaller thermal insulating value and proportionally higher acoustical insulating value, and vice versa. Such shields may be used, for example, between an object to be protected, e.g., thermally shielded, for example, the outer dash of an automobile, and a high temperature exhaust component such as a catalytic converter or manifold. Additionally, such shields may be designed to provide acoustical shielding and/or vibration isolation.
Known heat shields are often designed for use in vehicles such as automobiles and, as a result, are typically exposed to high and low temperatures. Some heat shields may also be exposed to a wide array of liquids, such as engine oil. Because exhaust gas temperatures in an internal combustion engine approach around 1050° C., there is a significant risk that thermally sensitive components within the passenger or engine compartment of the vehicle, which may be susceptible to such high temperatures, can be damaged. The engine compartment of the vehicle usually contains a multitude of temperature sensitive components that operate at temperatures lower than ambient air temperature in proximity to the exhaust line and a heat shield must be able to prevent this high temperature air from mixing with cooler ambient air near temperature sensitive components.
The uses of manifold shields with integrated manifold gaskets that avoid the problems outlined above are common. However, these solutions require separate forming tools and threaded fasteners at the powertrain assembly plant. Moreover, this solution is costly, heavy and does not facilitate installation and is subject to continuous and active design modifications to accommodate the continuous evolution of the powertrain assembly.
FIG. 1 is a highly stylized drawing showing a prior art heat shield 10′ and a gap that is oftentimes unable to be closed using the body of the heat shield. The heat shield 10′ has a metallic layer and is positioned over a heat source 60′, thereby forming a hot zone H and a cold zone C. The hot zone H is located at or around the location of the heat source 60′, and contains a volume of high temperature air, while the cold zone C is located away from the hot zone H and often includes lower temperature fluids, such as air and/or common automotive fluids. An edge of the heat shield 10′ is positioned next to the surface of a component 70′. This position serves to prevent the egress of hot fluid from the hot zone H and into the cold zone C, while also preventing the ingress of cold fluid into the hot zone H and away from the cold zone C. A disadvantage of this heat shield is the gap between the surface of the component to be shielded and the edge of the heat shield, allows the egress of hot fluid into the cold zone C and the ingress of cold fluid into the hot zone H. While FIG. 1 shows a heat shield 10′ having a substantial gap, gaps may be much smaller and still allow egress of hot fluid and ingress of cold fluid.
Current heat shield designs include heat shield components having a hemmed edge at the periphery of the heat shield and typically a deflecting portion. A disadvantage of such heat shields is that they do not efficiently provide a substantially airtight seal. Such heat shields, particularly in manifold exhaust applications, have gaps left between the edge of the heat shield and the component to be shielded. These gaps can allow gases and liquids to travel from exhaust manifolds to sensitive components or compartments, causing substantial damage. Damage to such components is often costly to repair, and in some cases, the components may be irreparable. Heat shields must be designed, therefore, in a manner that is effective in protecting components from being subjected to unwanted liquids and/or temperature differentials.
Even further, such heat shields frequently use a hemmed edge because the sharp edges of the heat shield can oftentimes be hazardous/dangerous to assemblers of the vehicles. In other words, the heat shield is typically one of the many components that must be handled by the assemblers, and providing heat shields with hemmed edges would protect against the risk of being injured by the sharp edges. Use of such hemmed edges, however, has little to no effect on air or liquid flow around the heat shield.
In view of the disadvantages associated with currently available methods and devices for providing a safe and effective heat shield, there is a need for a device and method that provides and maintains an effective air and/or liquid seal between the heat shield and component parts, and provides a lighter, more flexible and cost effective shield, while reducing the risk of injury during the assembly and/or manufacturing process.